Electric meter.



No. 698,646. Patented Apr. 29, |902.

T. DUNCAN.

ELECTRIC METER.

(Application med Feb. 2:73, 1599.) (No Model.) 3 Sheets-Sheet I.

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No. 698,646. Patented Apr. 29, |902.

T. nuNcAN.

ELECTRIC METER.

(Application filed Feb. 23, 1899.) f (No Model.) 3 Sheets-Sheet 2.

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No. 698,646. P atenfed Apr. 29, |902.

i T. DUNCAN., 4ELECTRIC METER.

(Application med Feb. 2s, 1899.) (un Madam 3 shuts-sheet 3.

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UNITED .STATES INPHATENT OFFICE.

THOMAS DUNCAN, OF FORTNVAYNE, INDIANA, ASSIGNOR TO THE SIEMENS dz; HALSKE ELECTRIC COMPANY OF AMERICA, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.

.ELECTRIC METER.

SPECIFICATION forming part of Letters Patent No. 698,646, dated. April 29, 1902. Application filed February 23, 18991. Serial No. 706.454. (No model.)

To 1f/ZZ whom it r11/Cty concern:

zen of the United States, residing at AFort Wayne, in the county of Allen, in the State of Indiana, have invented certain new and useful Improvements in Electric Meters; and I do hereby declare that the following. is a full, clear, and exact description of the invention, which will enable others skilled in the xo art to which it appertairis to make and use the same, reference being had to the accompanying drawings, which form part of this specification.

My invention relates to improvements in alternatingcurrent motor-meters of the inductive type for measuring both inductive and non-inductive loads, and more particu, larly to the class in which two magnetic fields are resolved into a common resultant, which zo is displaced ninety degrees or a quarter-period from the impressed electromotive force which it represents.

The object of the present invention is to provide an improved means for obtaining the z 5 desired phase relation between the'elds of the meter. In the preferred embodiment of the invention a magnetic ieldis produced that will lag behind the impressedelectromotive force by approximately two hundred 3o and seventy degrees, or the equivalent ofan advance or lead of ninety degrees or a quarter-period ahead of the impressed electromotive force. In meters o f this class and type it is customary to lag the magnetic Iield 3 5 which represents the pressure to ninety de- 1 grecs behind said pressure and in which case the current or ampere field-magnetism approaches closer'to the pressure or volt eldmagnetism on an inductive load, and if the 4o series current Was by some means caused to lag ninety degrees, then the magnetism of the series and shunt field-coils would be in4 phase and both a quarter-,period behind `the line-pressure.

In the present invention the magnetism which represents the electromotive force of the system is the equivalent ofhaving a ninety-degree advance of the pressure, and when a lagging current traverses the series or ampere field-,coil the angular displacement Be 1t known that I, THOMAS DUNCAN, a citi-4.

between the magnetism of the series field-coil `and the magnetism which representsthe pressure increases until they are a one-half pe riod or one h undred and eighty degrees apart, when theseries coil-magnetism lags to ninety degrees behind its pressure. In the first case, Where the phases of the series and shunt magnetism are in step, and in the second case,

Wherethey are one hundred and eighty degrees apart, and in which it is assumed that the series current lags ninety degrees behind the pressure, in both cases the torque exerted upon the armature will be zero, since the torque at any instance will be proportional to the sine of the angle between the magnetism of the series and shunt coils, and since the sine of both zero and one hundred and eighty degrees is zero there can be no rotation of the armature, the load being a wattless one.' Obviously when the load is a non-inductive one in both cases or in which the current traversing the series field-coil is approximately in step withthe impressed electromo tive force the magnetism of the pressure or shunt ieldfcoil inthe irst case will be ninety degrees aheadV of the line-pressure, and in the second case it willvbe. lagging behind said pressure by the same amount.

In the accompanying drawings, which form partof Vthis speciflcatiomand in which the reterence characters indicate like parts, Figure lis a vector diagram showing the relativeangles and magnitude of the various electromotive forces, currents, and magnetism identified in the invention. Figs. 2, 3, and e are front elevation views showing the series and shunt field-coils in section and in use with a disk type of armature; and Figs. 5 and 6 are sectional plan views of-the invention as applied to a cylindrical type of armature, all

of which are hereinafter more fully described.

In describing the invention with reference to Fig. 2 the series iield-coil 5 is traversed by the current which is supplied to the translating devices 6 by the `leads 2, 3, and 4 from the generator l and sets up a magnetic field in the coil 5 that is proportional to and varies with said current.

Adjacent to the lowerV face o the coil5 is an aluminium disk armature 9, mounted upon a suitable spindle '7, which is connected in any well-known manner to the registering device S for indicating the revolutions of said spindle. Upon the lower. side or face ot' the armature 9 are two shunt eld-coils and 19, each of which is traversed by a current that is proportional to and varies with the pressure in volts between the leads 2 and 4. 'l`o produce a rotation of the armature, there must be a difference in phase between the combined magnetism of these two coils 10 and 19 and the magnetism of the series coil 5, and, further, this difference in phase must be exactly ninety degrees to enable the meter to measure inductive loads. By this is meant that when the current through the series field-coil is nouinductive and its magnetism is in phase or step with the impressed electromotive force the magnetism of the coils lOand 19 must be in quadrature therewith, or ninety degrees from said series field-magnetism and said impressed electromotive force. The manuel' in which this is accomplished in the present invention is shown in Fig. 1, and in which the line E represents the impressed electromol tive force between the leads 2 and 4 ofthe system. The line 19C represents the angle and magnitude of the current'through the shunt field-coil 19. The line 20C represents the cur- Y rent through the primary 20 and its magnetism by the line 20, which is approximately at right angles to lhe impressed electrometive force E. The line E represents the secondary electromotive force generated in the transformer second-ary 23. The line 10a represents the current flowing through the shunt iield-coil 10, which is lagged behind the line E by the impedance-coil 11, and by combining the lines 10c and 19c into the resultant line m, which represents the effective or resultant magnetism of the coils 10 and 19, a ninety degree displacement from the impressed electromotive force E is obtained.

In adjusting the phase of the pressure-magnetism to exact quadrature the resistance 12 is employed in the usual manner.

The impedance-coil 1l is herein shown as assuming the form of a straight bar; but other and better forms may be used and such as will tend to give the greatest self-induction.

The magnetism of the series coil 5 will change its phase relation to the pressure, depending upon the self-induction of the translating devices, besides changing its strength with the iiow of current, and since the magnetic field of the shunt-coils 10 and 19 varies with the electromotive force in strength, but maintains a constant phase angle with the said electromotive force, it necessarily follows that the torque produced by these two magnetic fields upon the armature is proportional to the real or true watts.

To make the speed of the armature proportional to the torque exerted, a proper load or drag must be applied to the armaturesuch, for example, as a permanent magnet 24, which embraces aA portion of the disk armature 9 between its poles in a well-understood manner.

Fig. 3 shows an arrangement of the shuntcoils 10 and 19, having an iron core 18, forming the greater portion of this magnetic circuit, and the use of two series coils connected in series with each other. These series or ampere coils may be connected in parallel, if necessary.

Fig. 4 shows one series coil employed with the two shunt field-coils, the latter of which are not wound with their axes concentric, but occupy positions upon the respective poles of the iron core 18. The coil 10 is supplied by the current which lags somewhat less than two hundred and seventy degrees, and the coil19 is supplied by the current 19C, Fig. 1, setting up thereby a resultant magnetism 'm through the said core 1S, which is a quarterperiod ahead of the impressed electrornotive force.

Fig. 5 comprises two series field-coils 5 and a cylindrical armature 9, Within which are suitably mounted thepressure or shunt coils 10 and 19 and the iron core 18.. Fig. G also shows a cylindrical type of armature, but an arrangement of the energizing-coils in which the shunt-coils are exterior to the armature.

An indefinite variety of forms and modifications in the arrangement of the energizing-coils and armature may be employed as may be best adapted to the character of the work and size of the meter.

In the several figures of the drawings the wires 13 and 14 are shown as connecting the shunt-coils 19 with the supply-mains 2 and 4, the wires 15 and 16 as connecting the shuntcoil 10 with the secondary circuit 23 and the impedance-coil 11, and the Wires 21 and 22 as connecting the transformer primary 2O with the supply-mains 2 and 4.

Having thus described my invention, what I desire to secure by Letters Patent is- 1. In a system of distribution, the combination with an alternating-current generator, of a meter comprising a revoluble armature, a series field-coil in inductive relation with said armature, and a pressure field-coil for producing a field displaced two hundred and seventy degrees from the pressure, divided into two coils, one of said coils receiving its current from the secondary of a transformer, substantially as described.

2. In an induction-meter, the combination of a current-coil, au armature in inductive relation to said current-coil, and a pressurewinding comprising two coils, one of said coils receiving its current from the secondary of a transformer coupled across the circuitmains thereby to produce a phase diderence of two hundred and seventy degrees between the field of said pressure-winding and the pressure, substantially as described.

3. In a system of distribution, comprising IOO IIO

transmission-mains and a generator, of a mecomprising a revolubly-inounted armature, a series field-coil in inductive relation therewith, a shunt-Winding also in inductive relation to said armature, said shunt-Winding being divided into two coils, one of said coils receiving its current directlyfrom the transmission-mains, the second coil receiving its current from the secondary of the transformer included with the transmission-mains and be-A ing adapted to produce a stronger iield than the first aforesaid coil thereby to secure a phase displacement of two hundred and seventy degrees between the field of said pressure -winding and the impressed pressure, substantially as described.

4. In a meter, the combination With current and pressure windings for producing magnetic fields differing in phase, said pressurewinding being divided into two coils, one of said coils receiving its current from the source of supply, of a transformer receiving its cur-` rent also from said source, the other pressurecoil being included in the secondary circuit of said transformer and being adapted to create a vstronger magnetism than the first afore` said pressure-coil, substantially as described.`

5. In a system of distribution, the combination with an alternating-current generator,

of a meter having current and pressure wind-` ings for producing magnetic fields differing in phase, the pressure-winding being dividedr into two coils, one of said coils being `metallically connected with the source of current, of a transformer havingits primary metallically connected with the same source of current and its secondary included in circuit with the other of said coils, said coils being in inductive relation Wth'each other,the last aforesaid coil being adapted to create a stronger magnetic field than the first aforesaid pressure-coil, thereby to secure a phase displacement of two hundred and seveutydegrees between the magnetic field dueto such pressure- Winding and the impressed pressure, andan armature for said"meter ininductive relation withthe meter-windings, substantially as described. V

In a meter, the combination with a revoluble armature, of aseries coil inindlictive relation therewith, a shunt-winding also in inductive relation with said armature @divided into two coils, one of saidcoils receiving its current from the secondary of a transformer, said coil being adapted to create 'a stronger magnetic field than the rstl aforesaid pressure-coil, substantially as described.

7. In a meter, the combination with a revoluble armature, ofa series coil in inductive relation therewith, a pressure-winding also in inductive relation withsaid armature, said pressure-Winding comprising two coils, one of said coils being adapted formetallic inclusion with the source of supply, the 'second pressure-coil being adaptedfor inclusionwith the secondary of a transformer included with the source of supply, the last aforesaid coil being adapted to create a stronger magnetic eld than the rst 'aforesaid coil, thereby to secure a phase displacementof twohundred and sevmy A, D. 1699.` p

THOMAS DUNCAN.

Witnesses ADELAIDE KEARNs, `AUGUSTA VIBERG.

degrees between the field due to L the press ure-winding and the impressed pressure, 

